This application claims priority to an application entitled xe2x80x9cHelical Antenna Structure in Mobile Terminalxe2x80x9d filed in the Korean Industrial Property Office on Oct. 18, 2000 and assigned Serial No. 2000-61250, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates generally to a mobile terminal, and in particular, to an antenna structure in a mobile terminal.
2. Description of the Related Art
In general, a mobile terminal has a helical antenna formed in an outward protrusion and a whip antenna. When the whip antenna is contained in the mobile terminal, the helical antenna is operational, and when the whip antenna is extended, the whip antenna is operational.
FIGS. 1A and 1B illustrate the operations of antennas in a conventional mobile terminal. When a whip antenna 100 is contained in the terminal as shown in FIG. 1A, an RF signal is transmitted/received through a helical antenna 102 formed within a cap 106 which protrudes outward from a terminal 104. When the whip antenna 100 is pulled out as shown in FIG. 1B, the RF signal is transmitted/received through the whip antenna 100.
As shown in FIGS. 1A and 1B, the helical antenna is comprised of a winding coil and a cap covering the winding coil. The diameter of a top part TP equals that of a bottom part BP in the winding coil. Since the cylindrical winding coil is near to the outer surface of the cap, the helical antenna is significantly affected when it makes contact with a human body.
When the helical antenna operates, a high voltage is induced to the top part TP of the winding coil, and therefore this high voltage contacts cap 106 adjacent to the top part TP and a human body greatly influences the antenna""s characteristics.
It is, therefore, an object of the present invention to provide a helical antenna structure, where the influence of a human body on the antenna""s characteristics is prevented in a mobile terminal.
To achieve the above object, there is provided a helical antenna structure of a mobile terminal, which is minimally influenced by a human body. In the helical antenna structure, a cap protrudes from the upper end of the mobile terminal, and a winding coil is formed within the cap, which is spaced from an outer surface of the cap substantially the same distance from a bottom part of the cap to a top part of the cap.